Natural and constructed wetlands for ecosystem and engineering services in the arid and semi-arid regions

The Las Vegas Wash (LVW) has undergone significant wetlands degradation and soil erosion over the past thirty years due to increasing flow resulting from urbanization and large rainfall events in the Las Vegas Valley Watershed. The increased flow and associated pollution load in the LVW and its adverse impact in Lake Mead have alerted stakeholders to pay a greater attention to explore alternative measures for rehabilitation of wetland ecosystems. This dissertation, using the case of changes in LVW, analyzes and describes ecological and engineering services provided by wetlands in arid and semi-arid regions and provides a knowledge base that can be used to improve water quality and enhance stream restoration respectively. The dissertation includes three separate studies that are organized into three independent chapters. In the first study, constructed and naturally created wetlands in the LVW and its tributaries were studied to characterize and understand their potential role for improving ecosystem services (i.e., water purification). Excess nutrients and harmful metalloids removal was assessed at four wetlands, including Flamingo Wash Wetland, Pittman Wash Pilot Wetland, Demonstration wetlands at the city of Henderson water reclamation facility, and Las Vegas Wash Wetland. The study showed that the nutrient removal capacity of wetland vegetation in the four wetland sites correlated well with ambient nutrient concentrations in the sediments and water columns, irrespective of the type of plant present. For example, cattail and bulrush plant species have different nutrient uptake capacities, with these capacities mostly determined by the ambient nutrient and hydrologic conditions. Both species were equally efficient for nutrient uptake with high phosphorus concentration in below-ground and high nitrogen in above-ground plant parts. The below-ground parts of both species were capable of storing arsenic and selenium more efficiently than above-ground parts. However, bulrush species seem particularly efficient for removing metalloids as compared to cattail. These findings have important implications for improving our ability to engineer ecological solutions to the problem associated with common pollutants in the Las Vegas Valley. The second project analyzed the structural and functional attributes of increasing common reeds (Phragmites australis (Cav.) Trin. ex Steud.) and native cattails (Typha domingensis Pers.) for the best ecosystem services from large scale wetlands such as the one in LVW. The entire LVW vegetation was analyzed through mapping and ground truthing to estimate areal coverage of P. australis Vs. T. domingensis. The results from this study compared with the previously published data showed that P. australis population is increasing in most of the places. P. australis in comparision to T. domingensis, appears to thrive better in areas with altered hydrology and high nutrient inputs. In addition to its structural dominance, our data showed that P. australis plays a significant role in nutrient storage in wetlands. The net above-ground standing stock of nutrients in LVW wetlands was estimated to be approximately 26418.7 kg TN and 1264.1 kg total phosphorus (TP) for P. australis and 5183.8 kg total nitrogen (TN) and 272.8 kg TP for T. domingensis. Despite management concerns over P. australis dominance and growth, they fared quite well in nutrient storage in LVW wetlands compared to T. domingensis. The study concluded that in LVW, both T. domingensis and P. australis could be utilized for water quality improvement. It should be noted, however, plant uptake alone is not enough to improve water quality below regulatory thresholds from large scale wetlands, and managing dominant vegetation may be required for better nutrient removal efficiency. The third project studied the riparian wetlands function for their engineering services on streambank stabilization. The mechanical properties of native species (Artiplex lentiformis, Lycium andersonii, Larrea tridentata, and Allenrolfea occidentalis) were studied to understand their suitability in revegetation purpose on banks that are easily erodible. Field experiments were conducted to estimate root length, root length density, root area ratio, and root tensile strength. Finally, the root cohesion values were assessed using a simple perpendicular model and Fiber Bundle Model. The maximum root cohesion in the present study was estimated for A. lentiformis (97.6kPa) followed by L. andersonii (89.3kPa), L. tridentata (35.6 kPa), and A. occidentalis (34.8 kPa). These values were estimated to rank the native species for their potential use in bank stabilization. The results showed that these native and most prevalent species were more suitable for shallow bank slope stabilization, since their root distributions were significantly higher in topsoil depth (0-0.5 m) in comparison to subsoil depths (\u3e0.5 m). This information could be utilized for revegetation and restoration purposes in the arid and semi-arid regions where these plants are abundant

Effect of ultraviolet light treatment on microbiological safety and quality of fresh produce: An overview

Fresh and fresh-cut fruits and vegetables have been associated in several foodborne illness outbreaks. Although investigations from those outbreaks reported that the contamination with pathogenic microorganisms may occur at any point in the farm to fork continuum, effective control strategies are still being widely investigated. In that direction, the concept of hurdle technology involving a sequence of different interventions have been widely explored. Among those interventions, ultraviolet (UV) light alone or in combination with other treatments such as use of organic acids or sanitizer solutions, has found to be a promising approach to maintain the microbiological safety and quality of fresh and fresh-cut produce. Recent advances in using UV as a part of hurdle technology on the safety of fresh produce at different stages are presented here. Furthermore, this review discusses the mechanism of UV induced antimicrobial activity, factors that influence antimicrobial efficacy and its effect on produce. In addition, the challenges, and prospects of using UV irradiation as an intervention treatment were also discussed

Antioxidant Properties of Pecan Shell Bioactive Components of Different Cultivars and Extraction Methods

Pecan shells are a rich source of various bioactive compounds with potential antioxidant and antimicrobial properties. This study investigated the effect of pecan variety and method extraction on the antioxidant property of shell extracts. Twenty different varieties of pecan shells were subjected to either aqueous or ethanolic extraction and were examined for total phenolics and antiradical activity. The phenolic content and antiradical activity of shell extracts were significantly (p \u3c 0.05) varied with different pecan cultivars. The total phenolic content of ethanol extracts ranged from 304.2 (Caddo) to 153.54 (Cherokee) mg GAE/g of dry extract and was significantly greater (p \u3c 0.05) than those obtained by aqueous extraction. The antiradical activity of ethanol extracts ranged from 840.6 (Maramec) to 526.74 (Caper Fear) mg TEg−1, while aqueous extracts ranged from 934.9 (Curtis) to 468.3 (Elliot) mg TEg−1. Chemical profiling of the crude and acid hydrolyzed extracts was performed by reverse phase high performance liquid chromatography and flow injection electrospray ionization mass spectrometry. Lignin degradation products such as lignols, dilignols, trilignols, and oligolignols were found to be the major components of tested extracts. Phenolic content and antiradical activity of pecan shell extracts are significantly varied with cultivars and methods of extraction

Effect of pecan variety and the method of extraction on the antimicrobial activity of pecan shell extracts against different foodborne pathogens and their efficacy on food matrices

The shells of pecans are a rich source of bioactive compounds with potential inhibitory activity against various pathogenic microorganisms. This study investigated the antimicrobial activity of pecan shell extracts as effected by the type of cultivar and the method of extraction against various foodborne bacterial pathogens. Defatted shell powders of 19 different pecan cultivars were subjected to aqueous and ethanolic extraction (1:20 w/v) procedures, respectively. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of lyophilized pecan shell extracts dissolved in deionized water containing 5% DMSO (v/v) were determined against multiple strains of Listeria monocytogenes, Salmonella enterica, and Escherichia coli O157:H7. The antimicrobial activity of pecan shell extracts was found to be pathogen specific and strain dependent. Overall, L. monocytogenes was found to be least resistant to treatment with pecan shell extracts with an MIC and/or MBC values ranging from 1.25 to 5 mg/mL followed by Salmonella enterica (2.5 to ≥5 mg/mL) and E. coli O157:H7 (≥5 mg/mL). Type of cultivar and the method of extraction found to have a variable effect on the antimicrobial activity. Furthermore, the challenge studies on fresh-cut cantaloupes and thawed catfish fillets treated with 5 mg/mL pecan shell extracts and stored at 4 °C for up to 5 days showed aL. monocytogenes when compared to the controls with no treatment. No significant change in the color quality of treated food samples was observed with pecan shell extract treatment. The results of this study showed promise to use pecan shell extracts as a natural antimicrobial agent to inhibit the growth of tested foodborne bacterial pathogens

In-vitro Dissolution Study of Gallstone with Medicinal Plant Extracts

Background: Gallstone disease poses a substantial economic burden on healthcare systems globally, necessitating safer alternatives to current treatments like dissolution therapy and cholecystectomy. Natural compounds from plants offer a potential solution, but research on their cholelitholytic activity is limited. In vitro dissolution studies are crucial for identifying effective plant-based therapies. Objective: This study aims to investigate the in vitro cholelitholytic activity of six plants and Ayurvedic medicines, selected based on ethnopharmacological knowledge and folk medicinal practices. Methods: Gallstone samples were categorized as combined cholesterol gallstones (CCGS) or black pigment gallstones based on external morphology and cross-sectional analysis. In vitro dissolution studies were conducted using extracts from Bergenia ciliata, Berberis asiatica, Cuscuta europaea, Kalanchoe pinnata, Teraxacum officinale, Macrotyloma uniflorum, and Ayurvedic medicines (Cystone®, Gokshuradi, and Calcury). The samples were immersed in the extracts and controls separately and incubated in a shaking water bath. The gallstone dissolution capacity was assessed by recording the dry weight of the samples at multiple time points. Results: T. officinale was highly effective in dissolving black pigment gallstones, while B. asiatica exhibited superior efficacy for CCGS. M. uniflorum and C. europaea also demonstrated significant dissolution activity against black pigment gallstones. However, K. pinnata was less effective for both gallstone types. B. ciliata and C. europaea exhibited equal effectiveness against both types. Ayurvedic medicine extracts were less effective compared to plant extracts. Conclusion: This in vitro study showed the plants can dissolve GS effectively. However, the effectiveness of the plant to dissolve GS depends on the type of the stone. The findings from this study serve as a basis for further in vivo researc

In-vitro Dissolution Study of Gallstone with Medicinal Plant Extracts

Background: Gallstone disease poses a substantial economic burden on healthcare systems globally, necessitating safer alternatives to current treatments like dissolution therapy and cholecystectomy. Natural compounds from plants offer a potential solution, but research on their cholelitholytic activity is limited. In vitro dissolution studies are crucial for identifying effective plant-based therapies. Objective: This study aims to investigate the in vitro cholelitholytic activity of six plants and Ayurvedic medicines, selected based on ethnopharmacological knowledge and folk medicinal practices. Methods: Gallstone samples were categorized as combined cholesterol gallstones (CCGS) or black pigment gallstones based on external morphology and cross-sectional analysis. In vitro dissolution studies were conducted using extracts from Bergenia ciliata, Berberis asiatica, Cuscuta europaea, Kalanchoe pinnata, Teraxacum officinale, Macrotyloma uniflorum, and Ayurvedic medicines (Cystone®, Gokshuradi, and Calcury). The samples were immersed in the extracts and controls separately and incubated in a shaking water bath. The gallstone dissolution capacity was assessed by recording the dry weight of the samples at multiple time points. Results: T. officinale was highly effective in dissolving black pigment gallstones, while B. asiatica exhibited superior efficacy for CCGS. M. uniflorum and C. europaea also demonstrated significant dissolution activity against black pigment gallstones. However, K. pinnata was less effective for both gallstone types. B. ciliata and C. europaea exhibited equal effectiveness against both types. Ayurvedic medicine extracts were less effective compared to plant extracts. Conclusion: This in vitro study showed the plants can dissolve GS effectively. However, the effectiveness of the plant to dissolve GS depends on the type of the stone. The findings from this study serve as a basis for further in vivo researc

Muscle Relaxant and Sedative-Hypnotic Activities of Extract of Viola betonicifolia

The crude methanolic extract of the whole plant of Viola betonicifolia (VBME) was investigated for anxiolytic, muscle relaxant, sleep induction, antidepressant, and sedative activities) to ascertain its scientific values. VBME showed a significant (P<0.05) dose dependent anxiolytic action in staircase test. In muscle relaxant paradigms, a dose dependent muscle relaxation was observed. For phenobarbitone sleep induction test, VBME notably (P<0.05) reduced the latency time and increased total sleeping duration. Our tested extract was found free of any antidepressant activity, while the movement was significantly (P<0.05) shortened in locomotor activity. The whole plant of V. betonicifolia led to the isolation of 4-hydroxyl coumarin (4HC) which showed substantial safety profile in acute toxicity test. When challenged in Traction and Chimney tests, it showed significant (P<0.05) muscle relaxant effect in both muscle relaxant paradigms at 20 and 30 mg/kg during various assessment times. Nevertheless, 4HC was devoid of sedative and hypnotic potentials. In conclusion, VBME had strong muscle relaxant and sedative-hypnotic properties, while its isolated compound, 4HC, possessed a significant muscle relaxant action with substantial safety profile without sedative-hypnotic effects

Effect of hot water treatment of in-shell pecans on physicochemical properties and consumer acceptability of roasted pecan kernels

The effect of hot water pre-treatment of in-shell pecans on physicochemical properties, consumer acceptance and purchase intent of dehulled and roasted kernels was evaluated. In-shell pecans were first subjected to hot water at 70, 80 and 90 °C for 8.6, 6.6 and 4.6 min respectively and kernels were later dry roasted at 160 °C for 10 min. The physicochemical properties of hot water treated and untreated nuts, before and after roasting were determined. Furthermore, consumer acceptance and purchase intent of the roasted kernels were determined. Hot water treatment, alone and subsequent roasting had minimal effect on pecans’ physicochemical properties. Consumers liked (P \u3c 0.05) the colour and aroma of treated pecans. No effect (P \u3e 0.05) of pre-treatment was observed on the acceptability of other sensory attributes. Safety claim increased treated pecans’ overall liking; however, it decreased purchase intent. Hot water treatment showed promise as a post-harvest microbial intervention strategy without affecting the physicochemical properties and consumer acceptability

Hot water treatment as a kill-step to inactivate Escherichia coli O157:H7, Salmonella enterica, Listeria monocytogenes and Enterococcus faecium on in-shell pecans

In-shell pecans are susceptible to microbial contamination. This study was performed to investigate feasibility of using hot water treatment as a kill-step for food-borne pathogens during pecan shelling. In-shell pecans were subjected to hot water at 70, 80 or 90 °C for 1, 2, 3, 4 or 5 min. The time-temperature treatments to achieve a 5-log reduction of Salmonella enterica, Escherichia coli O157:H7, Listeria monocytogenes, and non-pathogenic Enterococcus faecium were determined. Thermal death values were determined for each tested condition. L. monocytogenes was most susceptible to heat treatment and were reduced by 4.6 ± 0.35 log CFU/g at 70 °C for 5 min, while 3–5 min at 80 and 90 °C treatments was required to achieve a similar reduction level for S. enterica, E. coli O157:H7, and E. faecium. S. enterica were most resistant and required 4 min treatment time to achieve a 5-log reduction at 80 and 90 °C. The D-values ranged from 1.15 to 1.72, 0.83 to 1.19, and 0.41–0.92 min at 70, 80 and 90 °C, respectively. E. faecium had the highest D-value (1.72 min at 70 °C), indicating a potential surrogate for process validation for pecan industries. Utilizing proper hot water treatment during pecan shelling could reduce food safety risk